minigallery: Astronaut candidates in pool

This summer, ESA's astronaut candidates have been splashing about at the pool - but not just for fun. They've been involved in 'extravehicular activity (EVA) pre-familiarisation', a vital part of astronaut training.

The six trainees had their first EVA course in June, in the Neutral Buoyancy Laboratory at the European Astronaut Centre, in Cologne, Germany. This laboratory features a huge water tank, where spacewalks can be practiced in 'neutral buoyancy', similar to 'weightlessness'. The uplift of the water offsets the pull of gravity, so the astronauts, wearing spacesuits modified for underwater operations, can train in near-real conditions.

Assisted by divers and mission controllers, the astronauts learn basic spacewalking concepts and skills, such as tethering to the International Space Station, the use of special EVA tools, communicating with an EVA crewmate and with the control room, and how to keep full situational awareness in a complex and challenging environment.